Statistical separation of schizophrenic patients from non- schizophrenic control subjects has been effected by the use of plasma protein fractions in model in vivo systems under "blind" conditions. One of the fractions contains alpha-2 globulins and the other contains gamma-G immunoglobulins. Our evidence is consistent with the hypothesis that a small, biologically active molecule attached to a carrier protein is responsible for the effects noted in the model systems rather than the interaction of a protein molecule with neural tissue. We are extending these observations to find out more about the chemical characteristic of the two fractions, if they can produce the same effects in the same test situation and if the biological activity of the globulin fractions can be related to the brain biogenic amines.